<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>JavaScript下拉菜单</title>
    <style type="text/css">
        * {
            padding:0;
            margin:0;
        }
        body {
            font-family:verdana, sans-serif;
            font-size:small;
        }
        #navigation, #navigation li ul {
            list-style-type:none;
        }
        #navigation {
            margin:20px;
        }
        #navigation li {
            float:left;
            text-align:center;
            position:relative;
        }
        #navigation li a:link, #navigation li a:visited {
            display:block;
            text-decoration:none;
            color:#000;
            width:120px;
            height:40px;
            line-height:40px;
            border:1px solid #fff;
            border-width:1px 1px 0 0;
            background:#c5dbf2;
            padding-left:10px;
        }
        #navigation li a:hover {
            color:#fff;
            background:#2687eb;
        }
        #navigation li ul li a:hover {
            color:#fff;
            background:#6b839c;
        }
        #navigation li ul {
            display:none;
            position:absolute;
            top:40px;
            left:0;
            margin-top:1px;
            width:120px;
        }
        #navigation li ul li ul {
            display:none;
            position:absolute;
            top:0px;
            left:130px;
            margin-top:0;
            margin-left:1px;
            width:120px;
        }
    </style>
    <script type="text/javascript">
        function displaySubMenu(li) {
            var subMenu = li.getElementsByTagName("ul")[0];
            subMenu.style.display = "block";
        }
        function hideSubMenu(li) {
            var subMenu = li.getElementsByTagName("ul")[0];
            subMenu.style.display = "none";
        }
    </script>
</head>
<body>
    <ul id="navigation">
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
            <a href="#">栏目1</a>   
            <ul>
                <li><a href="#">栏目1->菜单1</a></li>
                <li><a href="#">栏目1->菜单2</a></li>
                <li><a href="#">栏目1->菜单3</a></li>
                <li><a href="#">栏目1->菜单4</a></li>
            </ul>
        </li>
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
            <a href="#">栏目2</a>   
            <ul>
                <li><a href="#">栏目2->菜单1</a></li>
                <li><a href="#">栏目2->菜单2</a></li>
                <li><a href="#">栏目2->菜单3</a></li>
                <li><a href="#">栏目2->菜单4</a></li>
                <li><a href="#">栏目2->菜单5</a></li>
            </ul>
        </li>
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
            <a href="#">栏目3</a>   
            <ul>
                <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
                    <a href="#">栏目3->菜单1</a>
                    <ul>
                        <li><a href="#">菜单1->子菜单1</a></li>
                        <li><a href="#">菜单1->子菜单2</a></li>
                        <li><a href="#">菜单1->子菜单3</a></li>
                        <li><a href="#">菜单1->子菜单4</a></li>
                    </ul>
                </li>
                <li><a href="#">栏目3->菜单2</a></li>
                <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
                    <a href="#">栏目3->菜单3</a>
                    <ul>
                        <li><a href="#">菜单3->子菜单1</a></li>
                        <li><a href="#">菜单3->子菜单2</a></li>
                        <li><a href="#">菜单3->子菜单3</a></li>
                    </ul>
                </li>
            </ul>
        </li>
    </ul>
</body>
</html>